1. Field of the Invention
The present invention relates to a method and apparatus for connecting a first line to a second line. More particularly, this invention relates to a method and apparatus for connecting two or more lines using a remotely operable articulated connector.
2. Description of Related Art
In many industries, it is necessary to connect a first fluid-carrying or electrical line to a second line. In particular, the oil and gas industry regularly utilizes subsea pipelines that must be connected for the gathering and transportation of produced fluids.
There are several methods and devices currently used for connecting lines, and particularly, subsea lines. Methods known in the art include, for example, standard API or ANSI flanges. Alignment and installation of bolting may be performed using a diver or remote equipment. Tools that aid in the assembly of flanges may include alignment guides, modified bolts, or nut retainers. When a connection is made on relatively small pipes and in depths that are readily accessible by divers, the use of flanges has been historically acceptable. On larger pipes and in locations where accessibility becomes a problem for divers and intervention equipment, however, flanges become more difficult to use. Alignment of two flange halves is often time consuming and difficult. Engaging a nut on a bolt may be quite difficult in certain subsea environments. Manipulation and cross threading, which often present significant problems for divers, make many current remote connection techniques impractical.
One technique under development uses pipe handling frames to manipulate a pipe and to align flanges. Tooling must be included to install the sealing gasket and bolting. Examples of this equipment include the Sonsub Brutus system and the Stolt Comex Seaway Matis (Modular Advance Tie In System) System. Although these systems have shown some degree of utility, the equipment associated with this technique may be bulky and relatively difficult to deploy. A typical flanged connection system utilizing subsea rigging may have a length of about 32 feet, a height of about 8 feet, and a weight of about 38 thousand pounds. Mechanisms to install the bolting are usually located well inside the frames, and, therefore, access is often restricted to correct any problems with remote bolt manipulation.
Another technique uses a flanged connection system with a midline ball-and-socket type connector. Although this type of system introduces articulation into the pipe spool, the articulation exhibits significant drawbacks. Articulation at the midline location is often accompanied by X-Y translation at the point of connection. This may be additive to overall misalignment of the connection and may therefore create unwanted stresses near the connection point.
Another technique uses a DFCS (Diverless Flowline Connection System) flexible pipe connection system. This system incorporates a flexible hose. The use of the hose results in reduced stress at the point of connection compared to a rigid steel pipe. However, the hose is limited in use because of manufacturing limitations of size, collapse of the hose from the pressure in deep water, and incompatibility with some aggressive produced fluids that must be transported.
In addition to flange methods, there are other techniques for connecting two lines. One technique uses a clamp-type connector, and the clamp itself provides structural strength. The clamp may include two or more segments that may be drawn together with bolts. Some methods pre-assemble the bolts to avoid subsea assembly. The clamp engages two pipeline hubs, and the sealing is between the two hubs. Another method of engaging the hubs is to use a set of radially oriented collet fingers. The fingers may be rotated into position and provide the structural strength. A set of radially translated dogs may also be used as a locking mechanism. The hubs may be drawn together by the dogs in a manner similar to that of the collet fingers.
Although the above-noted techniques have demonstrated at least a degree of utility in connecting lines, significant room for improvement remains. For instance, such current techniques often require face-to-face contact, without angular misalignment, between lines in order for a successful connection to be made. Such required face-to-face contact means that subsea linear and angular measurements may become critical. For example, if a jumper spool is to be connected to two laterally spaced, upwardly facing pipelines, it is necessary to measure the linear distance between the two upwardly facing pipelines and precisely measure the angular orientations of those two pipelines before the connection may be made. Equipment for making such measurements, especially for making angular measurements, can be extremely costly and complicated, and the measurement process may add significantly to delays, thus further increasing costs in connecting lines. Further, errors in linear measurements may translate into angular errors during connection because angular flexing may be required to compensate for, for instance, a short or long jumper spool. Angular errors may significantly add to stresses occurring at a connection point. Such stresses may degrade a connection and may lead to a short product lifetime.
Other disadvantages may arise in current techniques due to the forces required to make a connection when misalignment is present. The determination of forces required to complete a connection is an integral part of the connector design process. During the installation of the connector, the application of force may be performed by bolting, clamping, collets, and dogs. The connection load is predetermined and is generally difficult to alter. In remote installations, the difficulty increases due to inaccessibility of the equipment. When a line and its final, intended location differ in linear and/or angular dimensions, there is additional unknown load that must be introduced to complete the connections. This is the load required to force the connections into alignment within the tolerance required for sealing. The misalignment may be a combined result of measurement error, pipe spool fabrication, gravitational, and thermal influencesxe2x80x94regardless of the source of error, however, the additional load required to connect the misaligned lines increases the probability of an unsatisfactory connection.
Another potential for failure of a connection using current techniques relates to damage to a seal or sealing surface during installation. Because current alignment techniques typically use seal surfaces for alignment, the seal often bumps, for example, a flange of another line during pipeline alignment. Such bumping may scratch or otherwise damage the seal, leading to a faulty connection. This increases the potential for damage to seals and sealing surfaces. When sealing surfaces used for annulus testing are also used for alignment, damage may occur, which may cause the annulus test to fail.
Many current techniques rely upon divers to facilitate the connection process. However, as subsea pipelines are installed deeper, it may become difficult for divers to connect lines. Other techniques may be suitable for divers, but financial concerns may dictate that divers may not be used because of their high cost. Therefore, a technique that may connect lines without divers, but that is inexpensive enough so that divers may be used if wanted would be desirable.
In current deep water connections systems, one of the driving cost factors is the cost of the installation vessel and its ancillary costs. These costs often greatly exceed the cost of the connector. Many activities, including measurement and subsea pipe manipulation to force alignment, may require extensive vessel time. A technique that could reduce installation time would therefore be advantageous.
Problems pointed out in the foregoing are not intended to be exhaustive but rather are among many that tend to impair the effectiveness of previously known connection techniques. Other noteworthy problems may exist however, those presented above should be sufficient to demonstrate that previous techniques appearing in the art have not been altogether satisfactory, particularly in providing a method and apparatus for quickly and inexpensively connecting one or more lines despite some degree of angular misalignment and without using a seal for alignment functions.
In one respect, the invention is a connector apparatus for connecting a first line to a second line and includes a hub, a sealing surface, a swivel coupling element, a seal, an alignment lip, and a clamp. The hub is coupled to the second line. The sealing surface is coupled to the hub. The swivel coupling element is coupled to the first line. The seal is coupled to and configured in operative relation with the swivel coupling element. The alignment lip is coupled to the hub and is configured to protect the seal and to guide the seal into mating engagement with the sealing surface. The clamp is configured to close about the swivel coupling element and the hub to draw together the seal and the sealing surface into sealing contact to connect the first line to the second line.
In other aspects, the connector apparatus may also include a grip and a ball nose. The grip may be configured in operative relation with the swivel coupling element, and the ball nose may be coupled between the grip and the seal. The ball nose may be configured to engage the alignment lip. The swivel coupling element may be positioned intermediate the grip and the ball nose to allow rotational and articulating motion of the swivel coupling element relative to the first line. The rotational motion may be 360 degrees, and the articulating motion may be about twenty degrees or less relative to the first line. The connector apparatus may also include an annulus testing port defined in the ball nose. The connector apparatus may also include a soft landing body, an alignment cone, and a landing base. The soft landing body may be configured in operative relation to the seal. The alignment cone may be slidably coupled to the soft landing body. The landing base may be coupled to the second line and may be configured to receive the alignment cone. The alignment cone may be configured to align the seal with the sealing surface by passing over an outer surface of the hub. The soft landing body may be configured to slide in relation to the alignment cone to guide the seal into seating alignment with the sealing surface. The hub may include a clamping recess configured to mate with the clamp upon closure of the clamp. The sealing surface may be recessed. The seal may be a ribbed metal seal. The connector apparatus may also include one or more guide pins and one or more guide cones in operative relation with the seal. The one or more guide pins may be configured to engage the one or more guide cones to guide the first line towards the second line. The sealing surface may be defined by the hub. The alignment lip may be defined by the hub.
In another respect, the invention is an articulated connector component including a swivel coupling element, a grip, a ball nose, a seal, and a clamp. The grip is configured in operative relation with the swivel coupling element. The ball nose is coupled to the grip and is configured in operative relation with the swivel coupling element. The swivel coupling element is coupled in a position intermediate the grip and the ball nose to allow rotational and articulating motion of the swivel coupling element. The seal is coupled to the ball nose. The clamp is configured in operative relation with the seal and operable to close about the swivel coupling element.
In other aspects, the connector component may also include a soft landing body in operative relation with the seal and an alignment cone coupled to the soft landing body. The soft landing body may slidably engage the alignment cone. The connector component may also include a support structure coupled between the grip and the soft landing body and may be configured to support the clamp about the seal. The seal and the ball nose may be integral. The seal and the ball nose may make up a replaceable sealing unit. The seal may be a ribbed metal seal. The rotational motion may be 360 degrees and the articulating motion may be about twenty degrees or less relative to a longitudinal axis of the connector component. The clamp may include a plurality of segments. The clamp may include a remotely operable clamp actuator. The clamp may include at least one pair of opposing sides, and rotation of the clamp actuator may advance the pair of opposing sides to close about the swivel coupling element. The connector component may also include an annulus testing port configured in operative relation with the seal. The annulus testing port may be defined in the ball nose.
In another respect, the invention is an articulating connector system including an active connector and a hub assembly. The active connector includes a swivel coupling element, a grip, a ball nose, a seal, a clamp, a soft landing body, and an alignment cone. The hub assembly includes a hub, a sealing surface, an alignment lip, a clamping recess, and a landing base. The grip is configured in operative relation with the swivel coupling element. The ball nose is coupled to the grip and configured in operative relation with the swivel coupling element. The swivel coupling element is intermediate the grip and the ball nose to allow rotational and articulating motion of the swivel coupling element. The seal is coupled to the ball nose. The clamp is configured in operative relation with the seal and operable to close about the swivel coupling element. The soft landing body is configured in operative relation with the seal. The alignment cone is slidably coupled to the soft landing body. The hub is coupled to the second line. The sealing surface is defined by the hub. The alignment lip is defined by the hub and is configured to protect the seal and to guide the seal into mating engagement with the sealing surface. The clamping recess is defined by the hub and is configured to mate with the clamp upon closure of the clamp. The landing base is in operative relation with the hub and is configured to receive the alignment cone.
In other aspects, the active connector may also include a support structure coupled between the grip and the soft landing body. The support structure may be configured to slide the soft landing body relative to the alignment cone. The rotational motion may be 360 degrees and the articulating motion may be about twenty degrees or less. The seal may be a ribbed metal seal. The connector system may also include an annulus testing port coupled to the active connector and configured in operative relation with the seal. The ball nose and the seal may be integral.
In another respect, the invention is a method for connecting a first line to a second line. An active connector coupled to a the first line is provided. The active connector includes a swivel coupling element; a seal in operative relation with the swivel coupling element, a clamp configured in operative relation with the seal, a soft landing body configured in operative relation with the seal, and an alignment cone slidably coupled to the soft landing body. A hub assembly coupled to the second line is provided. The hub assembly includes a hub, a sealing surface, a clamping recess defined by the hub, and a landing base configured in operative relation to the hub. The active connector is positioned adjacent the hub assembly. The active connector is hard landed by passing the alignment cone over an outer surface of the hub to engage the landing base. The active connector is soft landed onto the hub assembly by sliding the soft landing body relative to the alignment cone in a direction toward the landing base. The seal is seated into mating engagement with the sealing surface. The clamp is activated to close about the swivel coupling element so as to draw together the seal and the sealing surface into sealing relationship to connect the first line to the second line.
In other aspects, a remotely operated vehicle may perform the positioning, the hard landing, the soft landing, the seating, the activating, or any combination thereof. The active connector may also include an annulus testing port configured in operative relation with the seal, and the method may also include annulus testing the seal.
In another respect, the invention is a method for connecting a first line to a second line. An active connector coupled to the first line is provided. The active connector includes a swivel coupling element; a grip configured in operative relation with the swivel coupling element; a ball nose coupled to the grip and configured in operative relation with the swivel coupling element; a seal coupled to the ball nose; a clamp configured in operative relation to the seal; an annulus testing port configured in operative relation to the seal; a soft landing body configured in operative relation to the seal; and an alignment cone slidably coupled to the soft landing body. A hub assembly coupled to the second line is provided. The hub assembly includes a hub; a sealing surface defined by the hub; an alignment lip defined by the hub; a clamping recess defined by the hub; and a landing base configured in operative relation to the hub. The active connector is positioned adjacent the hub assembly. The active connector is hard landed by passing the alignment cone over an outer surface of the hub to engage the landing base. The active connector is soft landed onto the hub assembly by sliding the soft landing body relative to the alignment cone in a direction toward the landing base. The seal is seated into mating engagement with the sealing surface with the alignment lip. The clamp is activated to close about the swivel coupling element. The clamping recess is mated with the clamp. The grip is mated with the clamp. The seal and the sealing surface are drawn together into sealing relationship to connect the first line to the second line.
In other aspects, the method may also include engaging the alignment lip with the ball nose. A remotely operated vehicle may perform the positioning, the hard landing, the soft landing, the seating, the activating, the mating the clamping recess, the mating the grip, the drawing together, or any combination thereof. The method may also include annulus testing the seal with the annulus testing port. A remotely operated vehicle may perform the annulus testing.